The following are being investigated: utilization of full-sib families for the detection of linkages between a marker locus and quantitative character; measures, significance tests, and size and power of tests of linkage disequilibrium; a charge-state model and tests of neutrality; the number of neutral alleles in a finite population; behavior of apomictic plant populations; multilines with complex mixtures of genotypes; population genetics of tandemly repetitious DNA; path analysis procedures; inheritance and linkage of isozyme variants in maize; spontaneous mutations in Drosophila; allozyme variation and linkage disequilibrium in laboratory populations; electrophoretically silent variation; regulatory variation of enzyme actvities; introgression of teosinte into maize; and distance measures, evolutionary diversity and racial classification. Research methods are analytical and experimental. Experimental researchers are conducted mostly with maize and Drosophila.